is it necessary to ...

the issue im having is a lot of my LR has corals on it and i wasnt sure what to do i dont want them to die if i were to put them in the new tank....

 

Add all the base rock and as much live rock from your old tank as you want. Base rock does not cause a cycle. When people cycle the base rock in a new tank they use somehing to jump start it and help get the bacteria growing in the base rock. Because you won't be adding any die off to the tank, there will be no cycle. I would however recommend adding all your established live rock to start than slowly removing what you don't want in there. When you switch the tank over and move all your live stock, the tank will need all the bacteria in your current rock to handle the bio-load. as your base rock becomes live you will be able to slowly remove any live rock you don't want in favor of your new stuff.